Meet the download page of the Huawei rack server:

As you may see, there are only old versions of the BIOS and iBMC in the list. Now we will open newer ones. Click on one of the versions of the software you need.

When more information is appear, we can click "Other versions".

Ho-ho-ho! This is much better! Click at the newer version you like and go to the download page:

Click "download" at the top and get your brandnew firmware. 1288H V5 have 6.01 version for iBMC. It's cosmic fantastic!